Machines which automatically process food products are well known in the food industry. Such machines are invaluable in that they eliminate the cost of manual labor which is generally required for handling the food products during the manufacturing and pre-packaging processes. For example, food products, such as tortillas, typically are manually removed from an oven or discharged from a processing machine and then hand-counted and stacked for packaging. The labor cost incurred in manually counting and stacking tortillas substantially escalates the overall cost of tortillas. Thus, various machines have been introduced into the food industry for automatically counting and stacking tortillas or other similar food products, one of which is described in greater detail below.
U.S. Pat. No. 4,530,632 (hereinafter referred to as the '632 patent) discloses a machine wherein tortillas are placed on a first conveyor belt and moved down one end and along the underside of the belt. Contact between the tortillas and the belt is maintained by vacuum-creating air inlets formed in the belt. Flattening of the tortillas is accomplished by a flexible, stationary plate which is biased against the one end of the first conveyor belt. Specifically, as the tortillas are carried around the end of the belt, they pass between the biased plate and the conveyor belt. However, this bias often creates friction and/or promotes sticking between the moving tortillas and the stationary plate. Thus, it is standard industry practice to coat the stationary plate with Teflon paper to reduce friction and/or sticking between the moving tortillas and the plate.
After the tortillas have been flattened by the stationary plate, the tortillas are then dropped from the first conveyor belts onto a second or discharge conveyor belt positioned immediately beneath the first conveyor belt. The tortillas are stacked on top of each other and ultimately discharged by the second conveyor belt for packaging.
While the above-described machine, along with other article stacking, counting, and handling machines, may, in some instances, provide a means to more cost-effectively manufacture and otherwise process tortillas and other planar food products, they are often inadequate for reasons set forth below.
First, the known machines frequently have problems with inconsistent stacking of the tortillas attributable to numerous factors, including friction or sticking between the tortillas and the various machine components. For example, the Teflon-coated paper which covers the stationary plate of the '632 machine does not effectively eliminate friction or drag between the tortillas and the stationary plate during their contact. The presence of friction or drag, in turn, interferes with the precisely timed delivery of the tortillas to the discharge conveyor and results in inconsistent stacking.
Second, the above-described friction and sticking problems common to known machines often cause undesirable folding and breaking of tortillas which usually renders them unusable. Such folding and breaking problems are frequent occurrences in the Teflon-coated stationary plate of the '632 patent and are likewise not uncommon among the components of other machines.
Third, the known machines typically include problems with obstructions or blockages in machine components which often result from the previously described broken, torn, or folded tortillas. For example, breaks and tears in tortillas often ensue from friction generated between moving tortillas and the Teflon-coated stationary plate in the '632 machine. Again, such friction-induced breaks and tears result from the drag created on the uppermost side of the tortillas as they move beneath and contact the stationary plate. Such drag creates resistance which generally results in tears and breaks in the tortillas. If these tears and breaks sever the tortillas, then the severed portions may cause an obstruction or blockage within machine components. Consequently, it is often necessary to manually remove such obstructions and blockages which is both time-consuming and costly.
Fourth, the known machines typically require excessive ongoing maintenance, partly due to the aforementioned manual removal of obstructions or blockages. In addition, the Teflon coating on the stationary plate in the '632 machine requires frequent replacement. These and other maintenance related problems drastically reduce productivity and increase manufacturing costs.
Despite the numerous disadvantages with the known stacking, counting, and handling machines, including the machine in the '632 patent, they are still widely used in the food industry. Thus, while these machines may have some limited effectiveness in the manufacturing process of tortillas and other planar articles, they operate in a less than satisfactory manner.
Accordingly, an object of the present invention is to provide an apparatus for flexible, generally planar articles that consistently and uniformly stacks the articles.
It is another object of the present invention to provide an apparatus for stacking flexible, generally planar articles that reduces tears and breaks in the articles by eliminating friction between the articles and the various machine components.
It is another object of the present invention to provide an apparatus for stacking flexible, generally planar articles that eliminates unwanted folding in the articles.
It is another object of the present invention to provide an apparatus for stacking flexible, generally planar articles that prevents article-induced obstructions or blockages in the machine components.
It is another object of the present invention to provide an apparatus for stacking flexible, generally planar articles that moves imperfectly shaped or broken articles through machine components.
It is a further object of the present invention to provide an apparatus for stacking flexible, generally planar articles which may be incorporated into existing machines.
Other objects and advantages of the invention will appear hereinafter.